MEDIA ADVISORY

TO:                     News Directors, Education and Science Reporters

FROM:                 University Relations

SUBJECT:            UAF Researcher Co-author of Article in Journal, Science

DATE & TIME:     Friday, May 17, 2002

While the extinction of dinosaurs is now commonly attributed to the ecological effects of a comet or asteroid impact about 65 million years ago, scientists using new methods of analyzing sediment from the Triassic-Jurassic boundary, suggest the rise and subsequent 135-million-year reign of large dinosaurs may also have been in part due to an earlier comet or asteroid impact about 200 million years ago.

The research, featured in the May 17, 2002 issue of the journal, “Science,” brings together years of research into the duration, magnitude and probable cause of late Triassic floral and faunal extinctions in order to reconstruct the ecological conditions surrounding the dinosaurs’ rise to dominance during the subsequent Jurassic period. The authors conclude that the after-effects of an asteroid impact may have killed off or reduced many competitive reptilian groups, clearing the way for dinosaurs to diversify and flourish.

The article, “Ascent of the Dinosaurs Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary,” was co-authored by Sarah Fowell, a faculty member in the University of Alaska Fairbanks Department of Geology and Geophysics. Fowell was among a team of geologists who analyzed footprints, bones and plant spores in more than 70 locations in eastern North America. They also examined iridium dust and magnetic fields in four correlative sediment layers of the Newark Basin in present day New Jersey. Fowell noted that the abundance of fern spores increased briefly yet dramatically at the end of the Triassic period, coincident with the regional disappearance of several common Triassic plant types. Ferns are ecological opportunists, typically found in higher quantities after a catastrophic event.

“We submit that the demise of numerous non-dinosaurian reptiles and the subsequent, rapid evolution and diversification of the dinosaurs coincides with an ecological disaster that affected both the flora and fauna at the end of the Triassic period,” said Fowell. “Whether the event was an instantaneous collision with an extraterrestrial object or the result of a more protracted episode of volcanic activity or both, we cannot currently determine. Regardless, the growth of Jurassic dinosaurs in size and diversity can be viewed as the result of expansion into empty niches vacated by the mass extinction of their ecological competitors.”

-30-

CONTACT: Sarah Fowell, UAF’s Alaska Quaternary Center at (907) 474-7810 or e-mail ffsjf@uaf.edu.

CJB//05-16-02/02-071ma